Startled in a Starlet

I had enjoyed my previous sortie in it, but neglected aeroplanes can be risky, so first I inspected the airframe thoroughly.

Unable to find any good reason not to go, I soon jumped in and roared off.

After a careful engine runup, I whizzed off into the sky.

By now I was very ‘not happy Jan’ and wondering (and worrying) darkly about what might have happened to this airframe in the past few months.

Thanks to its powerful Jabiru motor allied to minimal mass, the Starlet’s acceleration was brisk. Like all its other controls, the short-coupled Corby’s rudder is light and sensitive, so there was no chance for a glance into the cockpit during our abbreviated takeoff roll.

Immediately upon getting airborne, I glanced at the ASI and thought, “Hmmmm, 30kt seems a bit slow, it looks more like 60 to me. Not to worry, hold that attitude and we’ll be fine. ” I climbed carefully straight ahead to 3000ft indicated, but it took quite a while and the earth sure looked a long way down below. “Hmmmm,” again.

I didn’t have a watch (oops) but it seemed to take a long time to get up here. Levelling off (ish), I throttled back. The indicated airspeed crept up to an unlikely 120kt with no increase in airflow noise. So, I clearly had a pitot/static problem – and since both the altimeter and the ASI seem to be affected, it was probably an obstruction in the static line. Not that this deduction would help me to get back on to the ground. At this stage, it was merely an interesting intellectual exercise.

Not to worry, I shall just have to do everything by attitude, but that should not present too many problems despite the Starlet’s light controls and limited pitch stability, typical of so many small homebuilts.

Nevertheless, I decided I had better do a couple of power-off stalls to check my maximum acceptable nose up attitude, and then a couple more with 1500rpm in a 30 degree banked turn to fix the approach attitude and get an idea of the anticipated sound levels.

So, I gently closed the throttle and slowed down. As expected, when its bright red nose got to around 10 degrees above the horizon, and with only the tiniest hint of warning buffet, the Corby pitched forward.

At that time, the ASI was still reading over 100kt, with the altimeter’s needle wandering all over the shop.

However, MUCH worse, the elevator’s feel had suddenly become weirdly non-linear.

Investigating further, as I gradually eased the stick very gently backwards, the nose bobbed up and down erratically through a small angle, and the feel force varied in odd, irregular increments. By now I was very ‘not happy Jan’ and wondering (and worrying) darkly about what might have happened to this airframe in the past few months, in the process becoming seriously concerned about structural and control integrity. Within minutes I had decided to terminate any further investigations and get back on to the ground as soon and as safely as possible.

Leaving the throttle nearly closed, I gently turned back to the airfield for a low speed descent. I did not want the airspeed to increase appreciably because, if there was some discontinuity or looseness in the elevator control circuit, any significant speed might induce flutter – which of course is usually fatal within a femtosecond.

I also did not want the increased half-Ro-V-squared to blow away anything that might now be less than completely secure. By this time I was unsurprised and unfazed that both the altitude and airspeed needles were all over their dials during the descent.

Flying a normal sized circuit at what seemed by observation to be around 1000ft, and then making a gentle, curving base leg by ear, feel and attitude, I set up a conservative, wings-level, pitch-level, low power final approach to our grass Runway 27.

Although it was shorter than the bitumen one, I chose the grass runway because of easier directional control at what might quite likely be a higher than normal touchdown speed and because of the reduced need for braking, given the grass’s drag.

I closed the throttle over the threshold and, being safely fast, floated, as anticipated, nearly the whole length of the runway.

I really didn’t feel very enthusiastic about going around, so I patiently stuck with this long float until the nose was up in to the three-point attitude and the airflow noise had gone really quiet. Once again the elevator’s feel was odd and fluctuating, and it became increasingly weird and wobbly the slower we got.

We eventually touched down on all three wheels right at the far end of the runway. Once we were definitely on the ground, I immediately switched off the ignition to get rid of any residual thrust from the propeller and induce a little prop drag, simultaneously easing backwards on the dual hand brake levers, so that I didn’t nose over in my eagerness to get stopped within the tiny remaining distance. We finally rolled to a halt in fact on the bitumen threshold of Runway 05. Sighing out a long-held and very stale breath, I taxied around to my friend’s hangar, to give him back his aeroplane with suitable words of encouragement and acclaim.

Then we drank beer (lots). It foamed a bit in my trembling hand, but nicely quenched my surprisingly dry throat.

As it turned out, there was some blockage deep within the static system (as I had kinda suspected) although it could not be discerned at the fuselage side vents. I wasn’t really too worried about that. ASI failure is fairly common, and should never be a cause for panic.

What really HAD worried me was that pitch anomaly.

This turned out to be because a length of self adhesive Mylar elevator gap seal under the left elevator had come unglued in its middle, but stayed attached (just) at both ends, it had bowed downwards a centimetre or so and was presumably changing its angle of attack randomly in the airflow like a Venetian blind slat to affect the airflow across the tailplane and elevator. Ok, so it wasn’t structural or really a true control problem, but it was no less frightening for that.

Once again the elevator’s feel was odd and fluctuating, and it became increasingly weird and wobbly the slower we got.